Pneumatic logic element

ABSTRACT

The disclosure of the invention is a diaphragm-type pneumatic logic element having two formed plates mounted in facing relation with complementary pairs of chamber recesses and interconnecting channel recesses formed in the facing surfaces of said plates, and a flexible diaphragm bonded to the facing surface of each plate excepting only a narrow area surrounding each chamber recess which is left unbonded. The improvement consists of a diaphragm support interposed between the diaphragms. The diaphragm support is a thin but relatively stiff sheet of material, preferably beryllium copper in the order of 0.002 inches thick, which is formed with apertures which register with and are of slightly larger diameter than the chamber recesses, but of less diameter than the usual unbonded area between the diaphragm and plate surrounding each chamber recess.

Unite Staes Alfred lliirt East Greenwich, Ml. [Ill] App]. No. 855,536

[72] Inventor North Kingstown, RI.

[54] PNEUMATlC LOGllC ELEMENT 6 Claims, 7 Drawing Figs.

[52} U.S.Cl 137/608, 92/102 [51] llnlLCl ..l1 161t 31/145, Floj 3/00 [50] Field of Search 92/102;

[56] References Cited UNITED STATES PATENTS 2,781 ,780 2/1957 Zahradka 137/608 3,318,329 5/1967 Norwood 137/608 X 3,322,148 5/1967 Rochte Q 3,426,800 2/1969 Bauer Primary Examiner-Henry T. Klinksiek Attorney-Martin Kirkpatrick ABSTRACT: The disclosure of the invention is a diaphragmtype pneumatic logic element having two formed plates mounted in facing relation with complementary pairs of chamber recesses and interconnecting channel recesses formed in the facing surfaces of said plates, and a flexible diaphragm bonded to the facing surface of each plate excepting only a narrow area surrounding each chamber recess which is left unbonded. The improvement consists of a diaphragm support interposed between the diaphragms. The diaphragm support is a thin but relatively stiff sheet of material, preferably beryllium copper in the order of 0.002 inches thick, which is formed with apertures which register with and are of slightly larger diameter than the chamber recesses, but of less diameter than the usual unbonded area between the diaphragm and plate surrounding each chamber recess.

PNEUMATIC LOGIC ELEMENT The present invention relates to an improved flexible diaphragm-type fiuidic device, and is an improvement upon a diaphragm-type logic device disclosed in the U.S. Pat. to Richard E. Norwood, No. 3,3l8,329 for Fluid Operated Logic Devices issued May 9, I967 The diaphragm-type logic device illustrated comprises two opposed plates having complemen' tary pairs of chamber recesses and interconnecting channel recesses formed in the facing surfaces of said plates, each plate having a diaphragm which covers and is bonded to the plate except for a narrow unbonded ring shaped area around each of the several chambers.

In constructions of the type described, it has been found that there is a tendency for the diaphragm under the wear and tear of continued operation to peel away from portions of the plate to which it is adhered, so that the effectiveness of the diaphragm in controlling the flow of air in the chambers and interconnecting channels is impaired and the effective life of the logic device is correspondingly shortened. Such diaphragm failures have occurred notably at points adjacent the several chambers where the diaphragms are unsupported on one side or the other owing to the presence of an interconnecting channel. A downward deflection of the diaphragms into the void created by such an interconnecting channel underlying the diaphragm will tend to rupture the bond between the top plate and its diaphragm. An upward deflection of the diaphragms into such a void created by an interconnecting channel overlying the diaphragms will tend to rupture the bond between the bottom plate and its diaphragm.

It is an object of the invention to eliminate any such tendency of the diaphragms to peel away from portions of the top and bottom plates to which they are adhered.

It is more specifically an object of the invention to provide means for additionally supporting the diaphragms adhered to the respective plates in a manner which will avoid such pulling away of the diaphragms and will ensure a long trouble-free operation of the logic device.

With these and other objects in view as may hereinafter appear a principal feature of the invention consists in the provision of a separating sheet of a very thin but relatively stiff material between the top and bottom plates and associated diaphragms bonded thereto, which serves as a support for portions of the diaphragms overlying interconnecting channels to prevent drawing the diaphragms into the voids created by said channels and the peeling of the topmost diaphragm from the plate to which it is adhered.

The several features of the invention will be fully appreciated by one skilled in the art from the following description taken in connection with the accompanying drawing, in which:

FIG. I is a plan view of a diaphragm-type logic device show ing the arrangement of chambers and interconnecting channels, and with certain areas in which stresses tending to cause peeling of the diaphragm from the plate to which it is adhered are set up indicated in dotted lines;

FIG. 2 is a plan view of the bottom plate only of said diaphragm-type logic device showing the arrangement of the chamber recesses and the interconnecting channel recesses formed therein;

FIG. 3 is a section taken on a line 3-3 of FIG. ll;

FIG. 4 is a section taken on a line 44 of FIG. 1;

FIG. 5 is an end view taken on a section line 5-5 of FIG. 1;

FIG. 6 is a plan view of the diaphragm support; and

FIG. 7 is a detail sectional view on an enlarged scale of outlet port C5 including the complementary chamber recesses, portions of the diaphragms adhered to the top and bottom plates, and the diaphragm support shown generally in FIG. 6.

The invention is herein disclosed as embodied in a threeinput signal diaphragm-type, or logic element I0, otherwise described as push-pull inverter, which consists of a top plate 12 and a bottom plate 14, which may be made from a transparent polycarbonate plastic, having their adjacent surfaces formed with complementary chamber recesses and interconnecting channel recesses which are enclosed by diaphragms l6 and 18 coextensive with the respective plates. The diaphragm I6 is bonded to the top plate 12, and the diaphragm 18 is bonded to the bottom plate 14, except for a narrow area around each of the chamber recesses in each plate which is left unbonded. The plates and diaphragms bonded thereto are secured together by suitable fasteners 20 passing through apertures in the plates and diaphragms. The three input signal logic element 10 shown is provided with three input signal control ports C1, C2 and C3, consistingof three-vent ridge-containing chamber recesses 22, 24 and 26 formed in the top plate 12, and complementary chamber recesses 28, 30 and 32 with signal control pressure inletsindicated at 29, 31 and 33 through the bottom of the bottom plate 14. Supply pressure is supplied from a supply pressure manifold 34 at the left side of the element as shown in FIG. 1, through a cross channel 35 and a restricted channel R1 to the ridge containing chamber recess 22, thence by an intercon' necting channel 38 to the chamber recess 24, by an interconnecting channel 40 to the chamber recess 26, and by way of a cross channel 41 and a restricted channel R2 to atmosphere. A control signal may be imparted to any one or more of the control ports C1, C2 and C3 through their respective control pressure inlets 29, 31 or 33 at a control pressure which may be 3 psi. Two output control ports are shown, designated at C4 and C5, having vent ridge containing chamber recesses 42 and 44 formed in the bottom plate and complementary chamber recesses 46 and 48 formed in the top plate 12. Supply pressure at 3 psi. is supplied from a supply pressure manifold 50 in the bottom plate 14 to the vent ridge containing chamber recesses 42 and 44 through channels 52 and 54 to an exhaust channel 55. The cross channel 35 formed in the top plate 12 connects the restricted channel R1 and the vent ridge containing chamber recess 22 of signal control port C1 with cha'mber recess 46 of control port C4. The cross channel 41 formed in the top plate 12 connects the vent ridge containing chamber recess 26 of signal control port C3 and the restricted outlet channel R2 with the chamber recess 48 of the output control port C5. Control ports C4 and C5 are formed with output passages 60 and 62 which extend downwardly through the bottom plate 14.

From an inspection of the drawing, it will be evident that the vent ridge containing chamber recesses 22, 24 and 26 of signal control ports C1, C2 and C3 are connected with one another by interconnecting channels 38 and 40, and to atmosphere by cross channel 41 and the restricted channel R2. The chamber recesses 46 and 48 of control ports C4 and C5 in the top plate 12 are connected respectively to the input and exhaust restricted channels R1 and R2, and to the vent ridge contain ing chamber recesses 22 and 26 of signal control ports Cl and C3 by cross channels 35 and 41. The vent ridge containing chamber recesses 42 and 44 of output control ports C4 and C5 in bottom plate 14 are connected to one another by interconnecting channel 54 and by channel 55 to atmosphere.

When no input signal is directed to any one of the three input signal ports C1 C2 or C3, the diaphragms at each of these input signal control ports will be open so that supply pressure passes from the restricted inlet channel RI, through each of the input signal ports in turn, and out to atmosphere through cross channel 41 and the restricted channel R2. Pressure is built up behind the restricted channel R2 sufficiently to close the diaphragm in outlet control port C5, as shown in FIG. 7, while the diaphragm in outlet control port C4 remains open, allowing supply pressure from the supply pressure manifold 50 to move freely into the vent ridge containing chamber recess 42 of control port C4 and then out through output passages 60 and 62. For this condition of the logic element in which control port C5 is closed, a downward strain is exerted tending to force the diaphragms into the void provided by the channel 55, which might be expected in time to cause a rupture of the bond between the top plate 12 and the diaphragm adhered thereto.

The application of a signal pressure to any one of the chamber recesses 28, or 32 through their signal input passages will move the diaphragm against the vent ridge of the complementary chamber recess 22, 24 or 26 and will, at the same time, exert an upward bending strain on the diaphragms tending to force the diaphragms into the void formed by the adjacent interconnecting channel. Continued repetition of this upward strain might be expected in time to cause the lower diaphragm to peel away from the bottom plate 14 to which it is adhered.

In accordance with the invention, the diaphragm-type logic element herein disclosed has been modified and improved by the addition of a thin but relatively stiff diaphragm support 66, which is assembled between the top and bottom plates 12 and 14 and their solvent bonded diaphragms l6 and 18. In the preferred form of the invention shown, the diaphragm support comprises an extremely thin, but relatively stiff sheet of beryllium copper, which in the illustration shown is 0.002 inches thick. Holes 68 formed in the diaphragm support 66 register with the complementary chamber recesses in the top and bottom plates, and are of slightly larger diameter than these chamber recesses, but of less diameter than the areas surrounding the chamber recesses in which the diaphragms are not bonded to the respective top and bottom plates. in the diaphragm-type logic element herein disclosed, each circular chamber is 0.195 inches in diameter, the unbonded area between each diaphragm and the associated plate including a chamber recess is 0.250 inches in diameter, and the hole 68 in the diaphragm support 66 concentric with each chamber recess and its inclusive unbonded area is 0.220 inches in diameter.

The relatively stiff diaphragm support 66 provides support especially for those portions of the diaphragms which overlie channels connected with the several chamber recesses. The voids into which portions of the diaphragms overlying the channels were formerly drawn are elimin,ated, together with any tendency of the diaphragm opposite the plate having the channel formed therein to peel away from the plate to which it is adhered. Places at which such peeling of the diaphragms away from the respective plates might have been expected to occur are indicated as shaded areas in FIGS. 1 to 4 inclusive. It will be noted in such case that the suspect area at which the failure might have been expected is located in the interconnecting channel at the point of egress of airflow from the associated control port, and that it is the diaphragm bonded to the opposite plate which tends to peel away. The insertion of the diaphragm support 66 between the top and bottom plates 12 and 14 and the diaphragms adhered thereto has entirely eliminated any such tendency of the diaphragms to peel away from the plates to which they are adhered, and, in consequence, has indefinitely extended the life expectancy of the logic element.

The apertures in the diaphragm support 66 have been made slightly larger than the chamber recesses in the respective plates and smaller than the unbonded areas between the diaphragms and plates surrounding the chamber recesses in order to provide adequate support for the diaphragms against separating strains, without at the same time constrictingthe movements of the diaphragms between their alternative on" and off positions.

While the invention has been particularly shown and described with reference to a preferred embodiment thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

l. in a pneumatic logic element having two plates disposed in opposed facing relation, said plates having complementary pairs of chamber recesses, and interconnecting channel recesses formed in said opposed faces, a flexible diaphragm adhered to each of said opposed faces, and me ans for holding said plates together, the combination of: I

a sheet 0 thin but relatively stiff material interposed between said plates and the diaphragms adhered to said plates;

said sheet having apertures;

one such aperture being disposed between each pair of complementary chamber recesses.

2. A pneumatic logic element according to claim 1 in which said chamber recesses and said sheet apertures are circular in shape.

3. A pneumatic logic element according to claim 2 in which each diaphragm is bonded to the adjacent plate in a manner to leave a narrow circular unbonded area about each chamber recess;

and the interposed sheet is formed with circular apertures larger than the chamber recesses and smaller than said circular unbonded areas about said chamber recesses.

4. A pneumatic logic element according to claim 3 in which said interposed sheet is of beryllium copper.

5. A pneumatic logic element according to claim 4 in which said sheet of beryllium copper is in the order of 0.002 inches thick.

6. A pneumatic logic element according to claim 5 in which each circular recess is in the order ofO. inches in diameter;

the unbonded area between each diaphragm and the associated plate is in the order ofO.250 inches in diameter; and the circular aperture in the interposed sheet of beryllium copper is in the order of 0.220 inches in diameter. 

1. In a pneumatic logic element having two plates disposed in opposed facing relation, said plates having complementary pairs of chamber recesses, and interconnecting channel recesses formed in said opposed faces, a flexible diaphragm adhered to each of said opposed faces, and me ans for holding said plates together, the combination of: a sheet of thin but relatively stiff material interposed between said plates and the diaphragms adhered to said plates; said sheet having apertures; one such aperture being disposed between each pair of complementary chamber recesses.
 2. A pneumatic logic element according to claim 1 in which said chamber recesses and said sheet apertures are circular in shape.
 3. A pneumatic logic element according to claim 2 in which each diaphragm is bonded to the adjacent plate in a manner to leave a narrow circular unbonded area about each chamber recess; and the interposed sheet is formed with circular apertures larger than the chamber recesses and smaller than said circular unbonded areas about said chamber recesses.
 4. A pneumatic logic element according to claim 3 in which said interposed sheet is of beryllium copper.
 5. A pneumatic logic element according to claim 4 in which said sheet of beryllium copper is in the order of 0.002 inches thick.
 6. A pneumatic logic element according to claim 5 in which each circular recess is in the order of 0.195 inches in diameter; the unbonded area between each diaphragm and the associated plate is in the order of 0.250 inches in diameter; and the circular aperture in the interposed sheet of beryllium copper is in the order of 0.220 inches in diameter. 